Prosecutors believe Zazi received explosives training from al-Qaida in Pakistan and may have planned to target mass transit in the New York City area.

"I'd like to stop this rush to judgement because what I've seen so far does not amount to a conspiracy," said Zazi's attorney, J Michael Dowling.

A law enforcement official confirmed yesterday that investigators had identified three people believed to have been in on the scheme. The official spoke on condition of anonymity because the investigation continues.

The accomplices are suspected of travelling from New York City to suburban Denver this summer and using stolen credit cards to help Zazi stockpile bomb ingredients, authorities have said.

"I don't know the names of anybody else that allegedly conspired with Mr Zazi," Dowling said. "Those names have not been produced."

Before authorities made a series of raids in the case, police detectives showed a source — a Queens imam at a mosque where Zazi had once worshipped — photographs of him and three people considered possible suspects, court papers say. It was unclear whether those three were the same ones suspected of travelling to Denver.

There have been no reports that the bomb-making materials have been recovered.

Prosecutors allege that Zazi has admitted that while living in Queens, he travelled last year to Pakistan and received explosives training from al-Qaida. Security videos and store receipts show that when he returned and moved to Aurora, Colorado, he and three others bought several bottles of beauty products over the course of several weeks, court papers said.

On 6 September, Zazi took some of his products into a Colorado hotel room outfitted with a stove on which he later left acetone residue, authorities said. He repeatedly sought another person's help cooking up the bomb, "each communication more urgent in tone than the last," the papers said.

The FBI was listening to Zazi and becoming increasingly concerned as the anniversary of the 9/11 attacks and a New York visit by Barack Obama approached, officials said. They decided to track him on 9 September when he rented a car and drove to New York.

On 10 September, Zazi told the Queens imam in an intercepted phone call that he feared he was being watched, court papers said. The imam later tipped Zazi off, saying police had come around and asked questions, the papers said.

Zazi cut short a five-day trip and flew back to Denver on 12 September. He was arrested a week later and initially charged along with his father and the imam with lying to investigators.

A letter filed by Brooklyn prosecutors last week argued that Zazi should be jailed indefinitely because, as an immigrant with ties to Pakistan, he could flee, and because he "poses a significant danger" to the community.

Evidence gathered — including bomb-making instructions found on his laptop computer — shows "Zazi remained committed to detonating an explosive device" until he was arrested, the letter said.